1. Field of the Invention
The present invention relates to a producing method of a semiconductor device, a producing method of a substrate and a substrate processing apparatus, and more particularly, to a producing method of a semiconductor device having a step for oxidizing a semiconductor wafer, a producing method of a substrate having a step for oxidizing a substrate, and a substrate processing apparatus for oxidizing a semiconductor wafer.
2. Description of the Related Art
In an oxidation system for forming an oxide film on a wafer surface under a normal atmospheric pressure by heating a wafer by a heater and flowing an oxidizing gas such as oxygen, as a method for equalizing an oxygen partial pressure to oxidize so as to enhance the uniformity of batches of oxide films, there is a method in which a flow rate of an inert gas is changed in accordance with a variation of an atmospheric pressure to equalize an oxygen partial pressure (see Japanese Patent Application Publication Laid-open No. H8-172084).
According to this method, however, when a plurality of kinds of gases which react with each other for oxidizing, for example, when oxygen and hydrogen are used for oxidizing in a pyrogenic oxidizing, etc., or when oxygen and dichloroethylene (C2H2Cl2: DCE) are used for oxidizing, it is not clear as to how a flow rate of the inert gas should be controlled, and if it is calculated from a flow rate of a gas or flow rates of gases which are to flow into a reaction chamber or an external combustion device, a total gas flow rate is varied if oxygen and hydrogen react with each other by the external combustion device as in the pyrogenic oxidizing. Therefore, there is a problem that a correction value is deviated and oxidizing can not be performed under a constant partial pressure of oxidizing gas or constant partial pressures of oxidizing gases.